I've been thinking a bit about origins of late, and the whole issue of human goodness and tendency to evil. Students in a course on science and religion I tutor on answered a question about evolution and "Original Sin". The more informed students understood that this phrase is often associated with Augustine. An Irenaean approach is more compatible with evolution, where there is no perfect past, just a humanity that is created in order to grow up and aspire to fully carry out the role of bearing the image of God.
I've also started reading Reason for Hope by Jane Goodall after hearing her speak recently. She's a Christian, though these days it seems of a more universalist persuasion if I've understood her right. She obviously has some insight into human behaviour and its origins by studying chimps.
In the end, regardless of how you view our material origins, Genesis 4 shows us what history has illustrated again and again, we are capable of great violence.
Cain kills Abel out of jealousy when God sees into the heart and prefers Abel's gift. When asked where he was, Cain asks "am I my brother's keeper?" This disavowal of his role to care for another human seems to me a rejection of his brother as also bearing the image of God. It has always been the case that violence against other humans is preceded by dehumanising them. The Holocaust is a shocking example of this, but I suspect much of what is felt towards asylum seekers who come by boat in popular thought, the unemployed in conservative thought, Indigenous Australians by those who'd deny them recognition in the constitution are all symptomatic of the inability to empathise because they have been dehumanised.
In a world where the lines on maps are often drawn by us, but where trade, greenhouse gases and pollution all flow over these lines, everyone is our neighbour. Given our shared genetic origins, everyone is a brother or sister. For Christians, there is a special sense of this "in Christ", this does nothing to diminish our need to regard everyone this way, for we are all in the "image of God". This means rather than being an object of violence, other people should be the subjects of our keeping: keeping safe, keeping well, keeping in filial relationship.
Blessed are the peacemakers.